import java.util.Scanner;

public class Test_3_24 {
    public static String toLowerCase(String s) {
        if(s==null){
            return null;
        }else{
            String ret="";
            for(int i=0;i<s.length();i++){
                char ch=s.charAt(i);
                {
                    if(Character.isLetter(ch)){//判断是否为字母
                        if(!Character.isLowerCase(ch)){//判断是否为小写字母
                            ch=(char)(ch+32);//大写字母的ASCII值加32，记得强转为char
                        }
                    }
                }
                ret=ret+ch;
            }
            return ret;
        }
    }

    public static void main(String[] args) {//https://leetcode.cn/problems/to-lower-case/
        Scanner scanner=new Scanner(System.in);
        while(scanner.hasNextLine()){
            String r=scanner.nextLine();
            String m=toLowerCase(r);
            System.out.println(m);
        }

    }
}
